Analysis volcano deformation for determining location of the pressure source, hypocentre and magma supply as disaster mitigation efforts: Case studies in Merapi volcano

Abstract

Various disaster mitigation efforts due to volcanic earthquakes and volcanic eruptions are carried out to reduce the risk of casualties and damage to infrastructure. One such effort is to conduct volcanic deformation studies. The results of this deformation study include estimating the position of the hypocenter, the pressure source, and the magma supply volume, so that the volume of material released during the eruption can be estimated. With the Mogi Model approach to analysis the Tiltmeter data on the eruption of Merapi Volcano in 2016, the estimated hypocentre is at a depth of about 1,100 to 2,440 m and the depth of the pressure source is about 2,345 m below the peak of Merapi with a magma supply volume of 21.81 million m3. With the same model approach from GPS data on the 2010 eruption, the results show that the hypocentre is at a depth of about 1,100 to 2,500 m below the peak of Merapi The source of magma pressure is at 2,200 m below the peak of Merapi and the volume of magma supply before the eruption is 15 million m3. These two results indicate that the depth of the pressure source causing surface deformation originates from shallow magma and is consistent with the seismicity analysis of Merapi in the same period.